IllegalArgumentException in AsciiDoc generation for Spring @EventListeners without parameters

[frademacher]

Hi all,

I'm currently experimenting with Spring Modulith 1.3.1 and found it to be a great initiative towards supporting the transition from Big Balls of Mud into properly structured monoliths. So first of all, thanks a lot for this :-)

However, I'm currently encountering an IllegalArgumentException when trying to generate AsciiDoc diagrams from an experimental codebase that uses a Spring @EventListener method to store initial data into an ephemeral H2 database. The method signature is as follows:

@Component
public class CatalogData {
    ...

    @EventListener(ApplicationStartedEvent.class)
    public void initialData() {
        // Invoke some save() operations in an injected repository
        ...
    }

The above code works flawlessly when running the Spring application. However, when attempting AsciiDoc generation using the following method

class ArchitectureTest {
    ...

    private static final ApplicationModules MODULES = ApplicationModules.of(App.class);
    void generateAsciiDoc() {
        var diagramOpts = Documenter.DiagramOptions.defaults().withStyle(Documenter.DiagramOptions.DiagramStyle.UML);
        var canvasOpts = Documenter.CanvasOptions.defaults();
		new Documenter(MODULES).writeDocumentation(diagramOpts, canvasOpts);
    }
}

I'm getting an IllegalArgumentException stating that

Method JavaMethod{....initialData()} must have at least one parameter!

from

spring-modulith/spring-modulith-docs/src/main/java/org/springframework/modulith/docs/Asciidoctor.java

Line 324 in 37b5840

Assert.isTrue(method.getRawParameterTypes().size() > 0,

The error is straightforward, and adding a parameter for the caught event and therefore changing the method signature to

    public void initialData(ApplicationStartedEvent event) {

fixes the issue.

Still wanted to report it, because Spring seemingly allows omitting the event parameter, while Spring Modulith seems to expect it.

[odrotbohm]

That's fixed and back-ported. In addition to the fix, we now properly document all event types listed in the annotation.